[Effect of non-restrictive external stent on the expression of platelet-derived growth factor in vein grafts of rabbits].
OBJECTIVE
To investigate the potential mechanism of non-restrictive external stent in preventing re-stenosis of vein grafts.


METHODS
Thirty-six rabbits underwent reversed bypass grafting of autologous external jugular vein into common carotid artery and then were randomly divided into two equal groups, stenting group (Group S), with an external stent 6 mm in diameter (Dacron vascular prosthesis) surrounding the vein graft, and control group (Group NS) , without stenting. The vein grafts were harvested 7, 14, and 28 days after the operation respectively. Immunocytochemistry was used to detect the platelet-derived growth factor B (PDGF-B) positive cells. The mRNA expression of PDGF-B was detected with RT-PCR.


RESULTS
The PDGF-B positive cell percentages in the intima of Group S 7 and 14 days later were both significantly lower than those of Group NS (15.2% +/- 3.6% vs 21.6% +/- 4.6%, and 6.5% +/- 2.6% vs 12.5% +/- 4.4%, both P < 0.05) . The PDGF-B positive cell percentages in media 7, 14 and 28 days later of Group S were all significantly lower than those of Group NS (13.8% +/- 4.6% vs 25.4% +/- 6.2%, 21.3% +/- 4.4% vs 35.7% +/- 7.3%, and 7.2% +/- 3.2% vs 19.2% +/- 5.4%, all P < 0.01). The PDGF-B positive cell percentage in adventitia peaked 28 days later in Group S and 14 days later in Group NS, and the PDGF-B positive cell percentage in adventitia 28 days later of Group S was significantly higher than that of Group NS (42.5% +/- 8.6% vs 31.9% +/- 4.6%, P < 0.01). RT-PCR analysis revealed that PDGF-B amplification products (457 bp) appeared in both group S and NS from 7 to 28 days, and the PDGF-B mRNA expression levels 7, 14, and 28 days later of Group S were all significantly lower than those of Group NS (31.2% +/- 6.5% vs 45.4% +/- 8.4%, P < 0.05; 42.3% +/- 6.2% vs 65.2% +/- 11.5%, P < 0.01; and 21.3% +/- 5.6% vs 36.2% +/- 9.4%, P < 0.01).


CONCLUSIONS
Non-restrictive external stenting can inhibit the synthesis of PDGF and change its distribution, which may be one of the mechanisms of external stent in preventing re-stenosis of vein grafts.
Tian
Xiao-dong
XD
Department of Thoracic Surgery, General Hospital of People's Liberation Army, Beijing 100853, China. tianxd301@sina.com
Gao
Chang-qing
CQ
Zhou
Nai-kang
NK
Li
Bo-jun
BJ
Xiao
Cang-song
CS
Liu
Xi
X
Zhang
Tao
T
D000818:Animals; D017536:Carotid Artery, Common / Q000601:surgery; D006083:Graft Occlusion, Vascular / Q000473:pathology / Q000517:prevention & control; D007150:Immunohistochemistry; D007601:Jugular Veins / Q000378:metabolism / Q000637:transplantation*; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015607:Stents; D014182:Transplantation, Autologous
D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger